Training device



April 6,'1948. R. E. KlT'rREDGE TRAINING DEVICE Filed Feb. 17, 1945 14 Sheets-Sheet l RAYMOND E. KITTREDGE INVENTOR.

April 6, 1948.

R. E. KITTREDGE TRAINING DEVICE Filed Feb. 17, 1945 14 sheets-sheet 2 90.75 60 45 30 I5 0 I5 30 45 GQ 7590 L R FIG. 1A m,

TARGET ALT ITU DE ANGLE ALTI ' TARGET GROUND RANGE HORIZONTAL REFERENCE L PLANE.

TARG ET Fl G. 2. B

COMPASS TARGET BEARING RELATIVE BEARING RAYMQND E.K|TTR-EDGE F y INVENToR. I Ll y BY F|G.2A Wf/M- ATTORNEYS April 6, 1948. R. E. KITTREDGE v 2,439,159

TRAINING DEVICE 'Filed Feb. 17, 1945 14 Sheets-sheet 5- FIG.2

/vp t a5 sq ab) i a fsoa 45 5 o, fa Y K/ s /f/ 5,60 53 6 "f l l Il O j 544- l n 5533 ne 1 l: f 554 535 o A MZ RAYMOND EKITTREDGE v INVENTOR;

FIG. 2 C

Wwf/M ATTORNEYS April 6,; 1948. R. E.K1TTREDGE l 2,439,169

' TRAINING DEvcE Filed Feb. 17, 1945 14 Sheets-sheet 4 FIG. 3 l RAYMOND E. KITTREDGE INVENToR.

ATTORNEYS VApril 6, 1948'. R. E. KlTTREDGE TRAINING DEVICE Filed Feb. l7 1945 14 Sheets-Sheet 5 POTENTIOMETER RAYMOND E.KITTREDGE INVENTOR.

i Av'ronnKEYs FIG. 4

April 6, 1948. R. E. KITTREDGE TRAINING DEVICE 14 Sheets-Sheet 6 Filed Feb. 1'7, 1945 RAYMOND E. KITTREDGE IN V EN TOR.

ATTORNEYS April 6, 1948.

R. E. KITTREDGE TRAINING DEVlCE Filed Feb. 17. 1945 14 Sheets-Sheet '7 RAYMOND E.K|TTREDGE INVENTOR.

BYW/ ffm' ATTORNEYS April 6, 1948 R. E. KITTREDGE I 2,439,169

TRAINING DEVICE Filed Feb. 17, 1945 14 sheds-sheet e FIG. 8 A 2f RAYMOND E KITTREDGE h' INI/ENTOR.

ATTORNEYS v April 6, 1948. R.u E. KITTREDGE I 2,439,169

TRAINING DEVICE Filed Feb. 17, 1945 14 Sheets-Sheet 9 RAYMOND E.K|TTREDGE 322v l INVENToR.

72a@ Y f, l

April 6, 1948. R. E. KlTTRl-:DGE

TRAINING-DEVICE Filed Feb. 17, 1945' 14 Sheets-Sheet 10 FIG-9C RAYMOND E.K|TTREDGE INVEN TOR.

FIG 9A Y 75A; ATTORNEYS April 6, 1948. i R. E. KITTREDGE TRAINING DEVICE Filed Feb. 17, 1945 14 sheets-sheet 1i a?? as? 360 RAYMOND E Kl TTREDGE INVENTOR. Mid/M" mmlll] FIG. 9B

.Illmmullllulqnlmmun mm lmmlulmnu April 6, 1948. R. E. KlTTRx-:DGE I TRAINING DEVICE Filed Feb. 17. 1945 14 Sheets-Sheet 12 RAYMONDE .KITTREDGE IN VEN TOR. V

ATTORNEY S 14 Sheets-Sheet 15 RAYMOND E.K| TTREDGE INVENT`OR.

April 6, 1948. R. E. KITTREDGE TRAINING DEVICE Filed Feb. 17, '1945 FIG.

` April 6, 1948, R. E. KITTREDGE TRAINING DEVICE Filed Feb 17, 1945 14 Sheets-Sheet 14 RAYMOND EQKITTREDGE INVENTOR.

` ATTORNEYS Patented Apr. 6, 1948 2,439,169j4 TRAINING BaymondjvE.. Kittredge, Binghamton?. Signorlto Aviation,

Ys?, asf., icolr, m1193150@ sppueatignsqhman 1v, laisserai Ncasea This inventionyrelatesg to a 'device for useln;

trairlrflglprsorml .in thelusefof rdaqgipent, and mere particularly.; mica triiltlllfle;- f Pet*- sonnel to fly an" airplane bylmeans. of" radar...

This application. is. a.@eliminatie-interi vtm?-` covfpending application Serial..NumberA 5272481 kind of radar screen or C scope l1 and ranggme ver IS tctwhiqhhe nilotoif @what Planelmay referfwhen; piloting` the plane; bgmeans' girada@ Fig.- lAJS'hQWtha the DQSfSQTen' afndzfang? meter. argsidebx Side. The pltsrsreepisfcomrmonly refer-redraw *1116.0 scnend hasfilpfon its faceapluralitypif horizontal as, Weill/as a fplualv n Q` 1f lilies` ,escale-,11S @miam-with, each `set of 1 es,anvd it willhe seen that thevcentrai vertical line is designated 0, while the" lines to either side of this zero linleare successively designatel -by increasing :incrementsof,` `15 up'. to 90 The horiecntalxlinesare.likewisefdesigmtedlin increasing increments; of -1`5 vfbegnnin g with; the designation of minus 20f or the V lowermdst line and. continuiriguift plus 60 f The raneametr 1ST pfovidaf with needle adapted to move over two scales one above-.the other, the cuter scale being graduated in-- miles from zero` toten Iand theinner scalebeing graduated in feet fromzero tqfifteenjthousandf Means are; provddzwherreby; the Scales. .are selectivelyusedf, clepencling; upon the distanceioif the ,targetV from; the radar qilppedzpla'rie- One typiealhuse of radar is in a lghterplane whichl is attempting to intercept a targetplane. It 1S this Particular Situatinwhih? thgpreierred. embodiment .,ovf my iriyention1 will be described; as simulating, althougrhrit will be readiljapparent thatthe invention mayfreadily'loe :appliedto the simulation ci all tYDQS 0f `r1at Vigtion byadar.

In order. that :the objects` onfliny" iinrentiorriV mayL bemorel Are{acllily'llniierstood the" geometrical relationships between a gh'terplaneand atarget plane should bebornein mine@ Inasmuch is assumed thatit-is-theghtermwhih is eqnippeq With radar, ittisthe pOStQn-Oi the targtmelativetotheghter which` is cqnsiqered Y Three ,factors vwill locate thesnosition `cut-the targetrelativetotheghter;

1i. Tar-getazimuth.angle,A whichzis the angle between the fighters longitudinal axis andiy the I dating equipictesagimuth up is; greater than vlll@Dinthe-scope. A" l l, 1Q is;A Y nQFijg, Qllkwhere the une LLLfdesignat diregtinof night andthe,ehtetslongimdinal theflineFl-"ra is the l line 'fsight from the iig o A,the -Tt'arg'et FmTa. designatesgthetprojectie o'fjjthelineof sight 'F4-Td on 4the` plane '369 through the lateral "carried by' avi-ealghter InE real radarcarried no part of this t used; Withjmwinf glzten her. hattet t0.y enable those. eld of radar to practice this in -4 venticrt. t

@animent carries; by a plane isset, in @pena-tions iriaY targetaplane be Iwithin. the.cldtqtomationof;,thelequipment an image SlLQh; aus H1315; SEQWQZF ign. 11A appears up 0n;tl1escree1.1;. t

range meter shows the Aslant range of the target from the fighter-in the illustrated case the slant 7 range being 81/2 miles. If the radar` equipment continues in operation, and the targety remains Within the eld of operation thereof, the position of the target relative to the fighter is continuously given by the scope and range meter. The position of the target relative to the axes of the ghter as shown by the scope and meter changesV in response tothe following movements' of the target: ,Y Y g 1 J 1. Changes in the latitude of the target;

2. Changes in the longitude of the target;

3. Changes in the altitude of the target.

Furthermore, the position of the target relative to the axes of the fighter as shown by the radar indicating meansjchanges in response to the following movements of the fighter:

4. Changes in the latitude of the fighter;

5. Changes in thelongitude of the lighter;

6. AChanges'in the altitude of the ghter;

7. Changes in the positionA of the fighter about its vertical axis; Y c

8. Changes in the position its longitudinal axis; 1

9. Changes in the position-of the its transverse axis.

As far as the first six mentioned factors vare concerned it is deemed unnecessary to show in detail how changes in each of these factors aifect the position of the target relative to the fighter in terms of the three basic concepts deined above.

It isclear that the relative 'positions of two points in space in terms of azimuth, angular difference in'jheight and distance vmay change as either point changes its position in anyone of the three possible 4directions of movement, or combinations thereof. Considering the last three mentioned factors, itis clear that a change in the position of the lighter about its vertical axis, i. e., a turning of the lighter, will produce a change in the` azimuth of the target. As faras factor 8 is concerned, let us assume that the target is 90 from the nose'of the'ghter, i. e., directly abeam, and that the fighter changes its position about its longitudinal axis-that is, it banks.' It is clear that the target elevation, angle will be changed by an amount equal tothe bank. And as far as the last mentioned factor is concerned, in the event the target is'directly ahead of the fighter, i. e., its azimuth is zero, a change in the ghters position about'its lateral axis-i. e., a diving or a climbingfthereof, Awill produce a change in the target elevation angle ,by an amount equal to the change about the lateral axis. Banking and pitching of a fighter plane variously7 affect target azimuth angle and target elevation angle, as is well understood by those skilled in the art. Y

My above mentioned patent closes means? forllfvaryingiitl indications -fof radar!y screen-Tand ange mete ccord'ingisumed `changesnl fthe).abovecmentireu actors whicni'in actuai-fiightcontrrrthe radar of the lighter about fighter about applicati@ fdistions. However, in that applicationith'eazimutli indication was not affected by assumed pitching and banking movements of the simulated radarequipped lighter plane, which, as will later appea-r, may form an important part of my invention. Also, the elevation angle indications were only approximately correct under circumstances of assumed pitching and banking of the simulated radar equipped lighter plane.

It is the basic object of my invention to pro-r vide means which will at all times change the vazimuth and elevation angle indications properly in response to an assumed pitching and banking which comprises a fuselage universally and rotatably kvmounted upon a stationary base. This trainer represents the fighter plane. The fuselage may bank, climb, dive and turn indenitely in either direction. The student in the fuselage, byrrneans of the rudder pedals in the fuselage which actuate a turning motor, may cause the fuselage to turn in either direction. vBy means of the control column or stick'whchv is also in the fuselage the student may cause the fuselage to bank, climb and pitch by means of the banking, pitching and climbing bellows whichare actuated by the movements of the control` column. All of these movements of the fuselage in and of themselves form no part of the present invention, and for a` complete disclosure thereof reference is made t0 United States Patents 1,825,462 and However, the instant inventionl discloses in the interior of the fuselage at a place visible to the student the `previously described radar indicating means, viz., the'C scope and range meter. Other types of radar indicating means may be readily adopted for use with my invention. Hereinafter in the description when a radar equippedp-lane is referred to, a plane equipped with the illustrated type of radar indicating meansis intended. Y I Y Upon a table remote from the trainer fuselage is a recorder which represents the target, and this recorder may under the control of an operator be'made to move in any direction and at varying rates across a Ychart on thetable. Therefore the direction and speed of horizontal movements of the target are simulated by the direction and speed of the target recorders movements. Y

Also mounted upon the same chart and table is a rrecorder which represents the fighter. This recorder is of the type described ln United States Patent 2,179,663. Its movement over the chart is automatically directionally responsive to changes in the headingY ofthe trainer and its speed of movement Vvaries according to thevassumed horizontal speed of the trainer. The direction and speed of horizontalr movements of the ghter are therefore simulated by the direotion and ,speed of this second recorders movements.- Thus, the position of the target recorder on the chart at all times represents the assumed latitude and longitude ofv the'target, while the position of the fighter recorder on the chart at all times represents the assumed latitude and longitude of the'ghter. Y

These-tworecorders are mechanically vcoupled and connectedf'ft'o the *lradarrindicating 4means s'o' that a #movement of? f'eitherl'onerelative flt'olthe other, throughA an intermediate "systemVof'ele'cev trical and :mechanicallEelementaH-lproduces the 5. same changes. in. theV positonior the imageon the radar scope S and vin fthe range metersf read-1 ing that correspondingtreal lchanges-V` inthe lati-2. tude. and longitudeA ofi .a realfftargetfand. of.'` a real `rlghter -wouldi produce on." the radar scope and meter inthe lighter.'

A` manual. control whereby. the operator may set into the mechanismtheassumed altitude of vthe target is.` provided, land. the. assumed: altitude A'of the. fighter is- Yautomatically changed. and introducedz-into. theapparatus as. willl'be later pointed out. the assumed.:altitude of the. fighter or of the targetis changed, through elec`-.. trical. and. mechanical! means,` the radar indie. eating means'are changedhjust` as are. the real radar indicating means. carried by a realiighter when corresponding realchanges inwtarget or iighter altitude occur. .l 1 1 Further, means are provided to change the radarindicating means in response to arturning, `banking and pitchingA of the fuselage ciV the trainer in simulation ofthe changeswhich occur in the radar indicating-meanscarried by a real fighter. when the. flghtenmakes correspondingmovements. Itshouldv be noted that the factors of target azimuthand.target.eleva' tion angle may changefinresponse to'the'turning,V banking, climbing and diving of 'theplane equipped with radar, and that the radar indicat-` ing *means` respond to these movements.` This-is because radar equipment. is designed.' to indicate the position. of the. targetilrelative to the lon.- gitudinal, lateral and v vertical axes ofthe radar equipped plane. Latitude, longitude and. altiture of the radar equipped planejalso` arexdetermining factors, but as vfar as. the target is concerned, the only determining lfactors are lati'- tude, longitude and altitude. In other words, the target may be considered to` be a point-having locationonly. j

Fig. 1 shows a groundedaviation. trainer of the type disc1osedin`U.`S. Patents 1,825,462-and 2,099,857` together with theghter and target recorders upon the table, the instructors con;- trol drawer kand information panel as wellas'the radar operators panel.

Fig,` lAis a detailed-.showing of. the: students Cseepeandrangemeter.` 'f

Fig. 2 isa detailed showingr of target recorders.; 1 Figs. 2A and; 2B illustrate some of therimportant terms usedherein. j i

Fig.. 2C is .adetaileddraW/ingof .a part ofthe mechanical triangulating means ofx'this. invention. -1 L Fig. 3 is a view of the instructors control panel andv information panel. 'i

Fig. 4 is a diagrammatic showing of many of the important parts of this invention; l Fig 5 is a detailed showing ofthe ghter recorder.AY i' l Figs. 5A, 5Brand 5C are detailed views of parts of theg'hte'r recorder.

Fig. 6 illustrates someof theK mechanism" of the Link trainer.

Fig. 6A shows the air speed indicator.

Figs. 7 and 8 areV a showingoftheghter recorder speed control means. 'K

Fig. 9 shows the attitude correction unit .and Figs. 9A, 9B, 9c. 9D, 9E,.'9F and` 'osare detailed parts of the 'attitude correction unit,y whilelfFig. en 1illustrates seine'of the'. denitions used herein' aswell as the principle offtlefattitude correction the center and unit. if v .Fig 10 isa viewer-the fighter.- altitude transe militer; 'i 'y Fig. 11 shows. the;y altitude'differentialunit Fig; -12: isa drawing of .the potentiometer drive erallyreferred to as a'Link Trainer.

Fig. 13isja schematic viewV of .the slip-.stream simulation control means.

Fig. 13A is` a detailed ViewA of. a portion ofthe apparatus of .Fig-.113; i

l The disclosed'embo'diment of luy-invention. in.. clud's in.` several place/sf the 'well .known system of i remote actuationifby.- teletorquesl and telegons. A 'general explanation. of' this` system is therefore believed? desirable'gl EachY 'of'.A thesel `systems in cludeslxa transmitterpand receiver suitably suppliedawithv .electrical energy rand connected. by means of a cable.: fiThe 'transmitter includes a housing fandLarotor, the' rotor usually. being referredtoas. theinputshaft. and the receiver also includes "a housing' and .'a: rotor, but" thefr'otor ot thev receiver isfreferredfto as the output shaft. When theV inputshaft ofthe transmitterjis turned in one direction,'=.the output shaftwof .the receiver simultaneouslymoves'in a corresponding direction and through the same angle,and when the input shaft moves inl thel reverse direction the output shaft moves" 'thel reverse direction through thesame angle.l By selectively coupling thetransmitter 'and"receiver', for a movement in oneV direction of theinput shaft lthe-output shaft may be `made to move in the desired direction. Teletorques areused when a relativelyV strong source of power'is available to move the input shaft; otherwise telegons'a'r'e employed. 'l

' The .fighter Referring nowto Fig. 1` it will be seen that my invention may include a trainerof 'the type gen This trainerwhiclris assumed inthe illustrated embodimentof my inventionv to be a `radar equipped fighter plane comprisesr a stationarybase l'and glfuselage 12; The fuselage l2'. is mounted upon a universal joint designatedv generally in Fig. 9 by I3 `which in turn rests upona main' central spindle'fld rotatablyfmountedin base Ill.V Octagon IE5-is: attached tofuselage l2 for rotation. therewith -byimeans of `cross arms |50, which are suitably attached to vertical `spindle Hl. The fuselage l2 is suciently large to accommodate a, studentwho may enterthe fuselage'by means of doorfl and.- a' seat (not shown) is provided within the fuselage for the student. A'hood ls maybe used to=completely encompass the student within the `trainer so* that inthe flying of the same he must rely completely. upon the instruments which are in the `fuselage |2'in a position corresponding tothe position of Athe instruments in areal plane.V The radar indicating C scope is designated Il and the range meter I9 andare mounted on the `instrument panel 18a; Within the fuselagel 2 'are a pair of rudder pedals 263 whichifsimulate the rudder pedals of a real'plane.Y By :a manipulationof these rudder pedals the student may7V energize* theturning motor 22 to cause the fuselage I2., universal joint I3, spindle M, cross arms! 5a. and Octagon I5 to rotate relafr tive tostationarybase [0in either direction about its vertical axis; just as the pilot of a real plane mayncorrespondinglyl 'cause theY plane to turn. Also, within the y*fuselage |21the`re is provided a control .stick or` `contro1v column 24',fasthe oase mayzbge, by1which the student may cause `the fuselage ..l2to"` dive or climbor'bank' relative to spindleflll, .crossfarmsilm Octagon l5` and base l in simulation of the divingcumbmg or banking of a real plane in actual night. The turning.

of fuselage l2 and associated parts isposs'ible because of the rotatable mounting. of spindle I4 in base I0, while the climbing, diving and .bank-l ing of fuselage I2 are made possibleby meansof the mounting of the fuselage l2 .upon the'previously mentioned universal 'joint I3. s l

The previously mentionedUnited States Patents 1,825,462 and 2,099,857 disclose in detail means for causing the fuselage l2 to turn, climb, dive and bank in simulationV of the movements of a real plane in actual flight. Therefore the movements of the rudder pedals and control stick by the student which control the' position of fuse- The` target recorder-Y' Seen upon chart 28 is the target recorder designated generally 30 and the ghterrecorder designated generallyr3l. The target recorder frame 32 is shown in Fig. 1 and thedetails of thisrecorder are shown in Fig. 2, to which referenceis'now made. It will be seen that thisrrecorderv comprises four upstanding Vlegs designated generally 33, each of the legs 33 being identical in construction and therefore only one of them is shown in detail. Referring to the leg 33 shown indetail it will be seenthat the legs 33 compriseV a tubular member 34 to the lowe'r end of each of which is rigidly attached the housing 35. Each tubular member 34 is rotatably mounted in the frame 32 of the target recorder. YUpon the upper end of each tube 34 isri'gidly aiiixed a worm vgear 36 driven lby a worm 31. For each leg v33 a horizontal shaft 38 is provided, rotatably supported rby the lower extremities of its housing 35 and a wheel 39 is rigidly mounted uponeach of these shafts, the vertical axis of eachwheel 39- being coin-l cident with the'verti'c'alaxis of the'associated tube34. -j

Means will now'be describedfor simultaneously driving each of the worms`31 which by means of its associated worm gear 36, tube 34 and housing 35 changes the position of its associated wheel 39 about its vertical axis in order that the'direction of travel of the target recorder 30 over :the chart 28 may be varied as desired by the instructor.

Referring to Fig. 1 it will be seen vtli'attable 26 is provided with a drawer 40 whicl'icontains a plurality of controls for the use of the instructor;v This control drawer is shown inv-detail in Fig. 3 to which reference is now made. In drawer'40 there is provided a variac or auto transformer 4l having a central shaft 42 upon the upperend of which is afxed Target Rate-v of Turn control knob 43. A pointer 44' is-affixed -to=shaft42 for rotation therewith, this pointer being arranged for movement overa scalef45 which is'atta'ched to the top panel 46 of 'drawer'Y 40. `Scale 45 is calibrated to 'show the simulated rate of turn of target recorder 30 in terms "of"A conventionalair'- craft turn indicator needle widths'- '.Variac 4|"is connected by means" of Ycable 41 'to the'reversible variablespeed target tur'n motor'f48 show riir'i4 Fig. 2. Cable 41 maybe'contained"inV cable Nrs-hewn in Fig. 1. The schematic connection of control knob V43, variac 4l, cable 41 and target recorder turn" motor' 48 is also shown in Fig. 4.

Knob 43, pointer 44,- dial 45, shaft 42 and variac 4| are so arranged that when pointer 44 is opposite an index mark upon dial 45, no voltage is placed across motor 48, and therefore the motor does not run. When pointer 44 is placed to one side of this index, the circuit is such that the motor'runs in one direction, the speed of the motor depending upon the distance that the pointer is placed Vfrom the index mark. On the other hand, when the pointer is placed to the other side of the index mark, the direction of output of the motor is reversed and its speed is` in accordance with the magnitude of movement of the pointer from the index. The details are not shown because they can easily be supplied by one skilled in the art.

In Fig. 2V it will be seen that the output shaft 50 of the target turn motor 43 has affixed thereupon worm 5I which drives worm gear 52 rigidly attached to horizontal shaft 53 upon the left end of which is mounted spur gear 54.1neshing with a driven spur gear 55 aixed upon horizontal shaft 56 which is carried by the frame 32 of target recorder 30 and which runs the entire width of the target recorder. Aiiixed upon each end of shaft 55 is a bevel gear 51, each of which drives a second bevel gear 58 rigidly aiiixed to a shaft 59, the shafts 59 being parallel with each other and perpendicular to shaft 56. Aixed upon each of these shafts 59 are two of the worms 31 which have been previously mentioned. Y

Thus by virtue of the just described arrangement whenever the output shaft 50 of the target turn motor 48 is rotated, worms 31 will simultaneously rotate each of the legs 33 of the target recorder in the same directionv and through the same angular distance, thereby causing a change in the' direction of the travel of the target recorder 30 over chart 23. Inasmuch as the turn motor 48 is reversible and of the variable speed type, the instructor may control the direction of turn of the target recorder as well as the rate of change of direction.

It should be borne in mind, however, thatthe whole target recorder 30 does not rotateabout its vertical axis but rather that the tub-es 39 are rotated with respect to the recorder frame, thus changing the direction of travel of the wheels 39 over the chart. The recorder frame 32 at al1 times remains in the same angular position relative to the lines of latitude and longitude upon the chart 28 at which it is placed when the problem is first set up. Y

Sti-ll referring to Fig. 2, there is rigidly afxed upon the middle portion of shaft 56, which is driven by turn motor 48, a bevel gear 60 which drives a second bevel gear 6l affixed upon the forward end of shaft 52 which lies perpendicular to shaft 55. Upon the rearward end of shaft 52 is worm 63 which drives worm gear 64, this worm gear lbeing rigidly mounted upon the upper'end of vertical shaft 55. Upon the lower end'of vertical shaft 65 is mountedspur gear 66 which drives a second spur gear 61. This last'spur gear is mounted upon' the input shaft 68 of target heading transmitter teletorque 69 which is'connected bymeans of cable 10. to target heading receiving teletorque 1l 'shownl in Fig. 3. .Aixed upon the output shaft (notashown) vof receiving teletorque 1| is needle 13 which isfree to move over dial 14 which is mounted in the front panel 15 of the instructors instrument box 16, rupon the top of forms the secondary input of the target speed drive differential |00. The rate of turning of the wheels 33 is in accordance with the output of differential |00. Inas-muchvas shaft 56 is rotated wheneverv the target turn motor 48 is running the secondary input gear ||'I of the target speed differential will bein motion.A If the target turn motor 48 is running in one direction, the output of target speed recorder differential is greater by an amount exactly sufficient to oiset the slowing down of the target recorder drive wheels 39 as a result of the turning of housings 35. IfA on the other han-d the target turn motor 48 is running inthe opposite direction the ,input gear of theY target recorder speed differential l'moves in the opposite direction and the output of itsdifferential is decreased by an amount exactly suflicient to overcome the increased rate of turning of the drive wheels 39 as a result of the turning of the housings 35 in that direction.

Referring now to Fig. l, a marking mem-ber ||8 is suitably held by a clamp ||9 to one of the legs 33 of the target recorder` 30. ".Uhis'marking member traces uponvthe chart 28 the path of the target recorder. v

Also shown in Fig. 2 are a pair of light sources |00a, including the projecting elements |0017, each angularly mounted to emit a ray of light which intercepts the chart 28 at thefpoint coin--V cident with the vertical axis of sleeve 283. This point represents the exact instant assumed position of the target plane. y Y

This invention therefore discloses a, target recorder arranged to move over a chart, map or the like at a speed under the controlof an instructor.Y This speed of movement-Which is proportional to the assumed speed of a target plane is shown upon an indicator which may be viewed by the instructor, The instructor may also control the direction of the target recorder aswell asthe rate of change of direction of the target recorder in accordance with the assumed rate of change in direction of a target plane. An indicator is provided to be viewed by the instructor for ascertaining the instant assumed heading of the target body, and a suitable marking device is provided to trace the path of the recorder over the chart.

The fighter recorder Referring now to Fig. 1, 'it has been mentioned that the ghter recorder is designated generally 3|. In Fig. 1 there is shown a gear |20 which is affixed upon the lower end of spindle |4-which turns whenever the trainer fuselage I2 is rotated with respect to the stationary base I0. This rotation of fuselage I2 is accomplished, as has been explained, Aby the `student `in the trainer manipulating the rudder pedals- 20. Meshing with gear |20 is a second gear |2| which is affixed upon the input shaft |22 of the fighter heading transmitting teletorque |23. This transmitter is connected by means of cable |24 to the lighter heading receiver teletorque |25 shown in Fig. 5. The schematic connection of fighter heading transmitter |23, cable |24, ghter heading receiver |25 and the fighter recorder 3| is shown in Fig. 4, and cable |24 maybe contained in the cable |24a shoWn in Figs. 1 and 5. A Suitable junction box |24c -is affixed upon recorder 3|. Referring now to Figs. 5 and 5A, the output shaft |26 of the fighter. heading receiver |25 has aflixed thereupon a disc |21 to which is attached an'arm |28 carrying a contact roller |29. Whenever the fuselage 2 is rotated about its vertical axis the input shaft of the fighter heading transmitter |23 lis rotated and as previously explained this will result in a rotation of the output shaft |26 of the receiver |25 through the sam-e angle and in the desired direction. The rotation of this output shaft |26 of course results in a rotation of the' contact roller |29. A

pair of contact segments |30 and |3| are provided and contact roller |29 bears against one of these segments or both of them at all times, depending upon their relative angular positions. The segments |30 and |3| are insulated from one another by virtue of the spaces |3|a, therebetween. These two segments are carried by the insulating disc |32 mounted upon shaft |33 for rotation therewith. Anouter brush ring |34 and an inner brush ring 35 are provided, each of these rings being carried by the insulating disc |32. The outer'ring |34 is in electrical Contact with the segment |3| by virtue of the'pins |35` while the inner ring |35 is in contact with the segment |30 by virtue of pins |31. Inner ring |35 is placed inside outer ring |34 concentric therewith and is insulated therefrom by suitable spacing. Outer collec-tor brush |38 bears at all times against outer brush ring |34 while inner brush |39 similarly `contacts. inner brush ring |35. AEach of these brushes is connected to the reversible drive motor |4|, the coil housing of which is lilla, bymeans of the conductors |49. The output shaft |42 of the reversible drive motor 4| has mounted thereupon a worm |43 inmesh with' worm gear |44 which is affixed upon vshaft |33. Another gear |46 is also mounted upon shaft |33 to be turned thereby.

vIn the operation of the mechanism shown in Fig. 5A, when contact roller |29 contacts both of the segments |30 and |3| motor |4| is not energized. However, when trainer fuselage I2 is rotated resulting in a rotationr of the input shaft |22 of lighter heading transmitter |23 shown in Fig. l the output shaft |26 of the fighter heading receiver |25 shown inY Fig. 5A also rotates and contact roller |29 is moved so that it contacts only one of the segments |30. or |3|. Assuming that Contact roller |29 contacts only segment |30, by means'of pins |37 inner collector ring |35, brush |39 and the conductor |40 which connects this brush to motor |4|, motor |4| is energized to turn in a given direction. The operation of motor |4| results in a rotation of shaft |42 and gear |43. Gear |43 drives gear |44 and shaft |33. The driving of shaft |33 simultaneously drives output gear |45 as well as the collector rings |34 and |35, insulating disc |32 and the contact segments |30 and |3|. Motor |4| will continue to run until the collector rings, insulating disc and gear segments |30 and |3| are rotated to such a position that both of the segments |30 and |3| contact the contact roller |29. At this point the drive motor |4| stops.

If, on the other hand, the rotation of the trainer fuselage |2 Were in such a direction that the Contact roller contacted solely the segment |3|, motor |4| would be energized to turn in the opposite direction. It would simultaneously rotate the output gear |46 and the collector assembly but the direction of rotation would be 

